Criteria for severe aplastic anaemia.

To study the validity of currently accepted international criteria for severe aplastic anaemia, 213 consecutive cases of bone marrow aplasia from a single institution were analysed. The distribution percentiles of peripheral blood values and multivariate analysis showed that the current reticulocyte count limit of 1% (corrected for haematocrit) is inadequate an an indicator of severe disease and should be substantially lowered. Since the choice of treatment in aplastic anaemia may depend on the prognosis current criteria for severe aplastic anaemia should be modified.